How to convert centimetres to millimetres
One centimetre equals 10 millimetres, so multiply the number of centimetres by 10:
mm = cm × 10
cm = mm ÷ 10 (1 mm = 0.1 cm)
Example: 0.1 cm → 0.1 × 10 = 1 mm.
Going the other way, divide by 10, or multiply by 0.1; the millimetres to centimetres converter does it for you.
Everyday values
| Centimetres | Millimetres | For example |
|---|---|---|
| 0.1 cm | 1 mm | one millimetre |
| 1 cm | 10 mm | ten millimetres |
| 2.54 cm | 25.4 mm | one inch |
| 5 cm | 50 mm | 5 cm |
| 10 cm | 100 mm | 10 cm |
When you need this conversion
Multiply centimetres by 10 to get millimetres. Rainfall, jewellery sizes, screws and phone dimensions are usually given in millimetres.
Centimetre to millimetre conversion table
| cm | mm | cm | mm |
|---|---|---|---|
| 0.5 cm | 5 mm | 6.5 cm | 65 mm |
| 1 cm | 10 mm | 7 cm | 70 mm |
| 1.5 cm | 15 mm | 7.5 cm | 75 mm |
| 2 cm | 20 mm | 8 cm | 80 mm |
| 2.5 cm | 25 mm | 8.5 cm | 85 mm |
| 3 cm | 30 mm | 9 cm | 90 mm |
| 3.5 cm | 35 mm | 9.5 cm | 95 mm |
| 4 cm | 40 mm | 10 cm | 100 mm |
| 4.5 cm | 45 mm | 10.5 cm | 105 mm |
| 5 cm | 50 mm | 11 cm | 110 mm |
| 5.5 cm | 55 mm | 11.5 cm | 115 mm |
| 6 cm | 60 mm | 12 cm | 120 mm |
About the units
- Centimetre (cm): one hundredth of a metre.
- Millimetre (mm): one thousandth of a metre.
Both are units of length. The conversion factor comes from the exact definitions above, so the calculator is exact; results are only rounded for display (up to six significant digits).
Frequently asked questions
How many millimetres are in one centimetre?
One centimetre is 10 millimetres. One millimetre is 0.1 centimetres.
How do I convert centimetres to millimetres?
Multiply the value in centimetres by 10. To go back, divide by 10.
What is 0.1 cm in millimetres?
0.1 cm = 1 mm.
What is 2.54 cm in millimetres?
2.54 cm = 25.4 mm.
Sources
- NIST Special Publication 811 (2008), Guide for the Use of the International System of Units (SI), Appendix B: conversion factors.
- NIST Handbook 44 (2024), Appendix C: General tables of units of measurement.
Last reviewed 5 October 2026. Results are estimates; see our disclaimer.